Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.
J Chem Phys. 2012 Feb 7;136(5):054110. doi: 10.1063/1.3681396.
The recently proposed full configuration interaction quantum Monte Carlo method allows access to essentially exact ground-state energies of systems of interacting fermions substantially larger than previously tractable without knowledge of the nodal structure of the ground-state wave function. We investigate the nature of the sign problem in this method and how its severity depends on the system studied. We explain how cancellation of the positive and negative particles sampling the wave function ensures convergence to a stochastic representation of the many-fermion ground state and accounts for the characteristic population dynamics observed in simulations.
最近提出的全组态相互作用量子蒙特卡罗方法允许在不了解基态波函数的节点结构的情况下，对相互作用费米子系统进行实质上更精确的基态能量计算，其大小远远超过以前的可处理范围。我们研究了这种方法中的符号问题的本质以及它的严重程度如何取决于所研究的系统。我们解释了如何通过正粒子和负粒子对波函数的抽样的抵消来确保收敛到多费米子基态的随机表示，并解释了在模拟中观察到的特征种群动态。
